Hosting your own instance starts off with paying out of pocket then once you set up donations from the community those dollars would fund most of the operating costs. However as the instance gets larger the economies of scale improve and eventually you may have some money leftover to put aside. You could also sell merch of the logos like stickers to help with keeping the lights on.

A lemmy instance needs a domain name, a host and a smtp email for notifications.

I wonder what the Lemmy.world server operations are like.